I'm new to Ubuntu (using 16.04), I've used it for about three days.
Today's issue is that the menu bars are missing from some applications: Nautilus, archive manager, Sublime Text 3 (when not run with sudo)*, Evince and who knows how many others. I swear they were present yesterday.
On the other hand in Firefox, LibreOffice and on many others, they are still present, for now.
I changed "show the menus for a window" under settings/appearance/behavior
both to "in the menu bar" and "in the window's title bar", but that didn't fix it.
Uninstalling and reinstalling the applications didn't fix it either.
What can I do?
edit, pics! https://i.sstatic.net/eO4GV.jpg
*When I open Sublime Text from the Unity Launcher or when I type subl in the terminal, menus are not showing. If I type sudo subl they do.